Driving and positioning mechanism for drum type controller



Oct. 13, 1959 c. F. ROBBINS 2,908,175

DRIVING AND POSITIONING MECHANISM FOR DRUM TYPE CONTROLLER Filed July 2, 1957 5 Sheets-Sheet 1 Oct. 13, 1959 c. F. RCBBINS 2,

DRIVING AND POSITIONING MECHANISM FOR DRUM TYPE CONTROLLER Filed July 2, 1957 s Sheets-Sheet 2 Oct. 13, 1959 c. F. ROBBINS 2,908,175

DRIVING AND POSITIQNING MECHANISM FOR DRUM TYPE CONTROLLER 3 Sheets-Sheet 3 Filed July 2, 1957 United States Patent DRIVING AND POSITIONING MECHANISM FOR DRUM TYPE CONTROLLER Clyde F. Robbins, Milwaukee, Wis., assignor to Cutler- Hammer Inc., Milwaukee, Wis a corporation of Delaware This invention relates generally to. drum type con trollers for electrical devices.

More particularly the invention relates to mechanisms for driving and positioning the rotatable drum cylinder of heavy duty controllers. I

When rotating the drum cylinder ofcontrollers, particularly those designed to handle extremely large values of current, overtravel of the cylinder or failure to stop exactly at a desired position may accidentally establish and/or interrupt electrical vcontact between certain of the movable and stationary contact members employed in the controller.

Thus, arcing may occur causing welding, pitting, buming and other types of damage to the contact members and other portions of the controller. Some mechanisms dependent on the skill of the operator to attain accurate drum cylinder positioning have proven unsatisfactory. Therefore, it is desirable to provide improved means for driving and positioning drum cylinders.

It is an object of this invention to provide improved means for rotating the drum cylinder of electrical controllers whereby accurate drum cylinder positioning is obtained and over-travel is prevented.

Another object is to provide such meansv which positively rotate the drumcylinder a predetermined distance during each operation.

Still another object is to provide such means whereby thereof without, departing from the scope of the appended claims. I

In the drawings Figure 1 is a top plan view of the driving and positioning mechanism associated with a, drum type controller;

Fig. 2 is a rear el'evati'onal view of the mechanism shown in Fig. l; v

Fig. 3 is a cross sectional view along line 33 of Fig. 1;

Fig. 4 is an enlarged cross sectional view of an ele merit of the mechanism; and

the drum cylinder may be rotated step-by-step in either of the mechanism taken Fig. 5 is a front elevational view-showing a portion of the mechanism.

In the drawings, the numeral 11 designates a heavy duty drum type electrical controller comprising a frame and a rotatable drum cylinder (not shown), the shaft 120i which is supported at its lower end by bearing r'neans (not shown). The upper portion of shaft '12 extends through an opening in a bearing plate 1 3' whi'ch'is bolted 2,908,175 Patented Oct. 13, 1959 ice to the top surface of the frame of the controller and the upper end of the shaft is supported by bearing means 14 carried by a bearing support member 15. Bearing support 15 is bolted to bearing plate 13.

Referring to Fig. 3, the hub 16 of a star wheel 17 is rigidly affixed to shaft 12 so that rotation of the star wheel effects rotation of the drum cylinder. The star wheel shown has nineteen notches, each spaced an angular distance of seventeen degrees from an adjacent notch, and the sides of each notch meet to form a right angle. A portion of the star wheel is unnotched, as Fig. 1 shows.

A bevel gear 18 secured to shaft 12 meshes with another bevel gear 19 which is secured to a shaft 20 supported by hearing support 15. Gears 18 and 19 and a portion of shaft 20 have been deleted from Fig. 1 to a control panel 22. The panel is attached to, or may merely have a fixed position with respect to, the frame of the controller 11. A hand wheel 23, the purpose of which will hereinafter be explained, is secured to the end of shaft 21 projecting from the face of the panel. The hub, of the handwheel 23 has a pointer 23a intergral therewith which indicates by its position with respect to indicia provided on the face of panel 22 the contact position. of the drum cylinder, as Fig. 5 makes clear.

Two independently movable levers'or operating members 24 and 25, each of which has a circular-hole through Fig. 3 shows, suitable spacer washers 26 and 27 are disposed on the hub between the star wheel and lever 24 and between both levers, respectively. A resilient retaining ring 28 which is securely in a groove formed about the upper end of hub 16 serves to hold the levers and washers on the hub.

As Figs. 1 and 2 make clear, the outer ends of the levers. 24 and 25 are pivotally connected to the angle brackets 29 and 30, respectively, by the pins 31 and 32, respectively, and the brackets, in turn, are rigidly secured to the threaded ends of the push rods or tie rods 33 and 34, respectively, by pairs of adjustable securing nuts. For convenience in illustration, Figs. 1 and 3 show the rods 33 and 34 (which are movable to pivot the levers) as broken, but it is to be understood that the rods are single, continuous lengths of material substantially equal to each other in length. The rods 33 and 34 extend through the bushings 35 and 36, respectively, which are secured to panel 22 by the nuts 37 and 38, respectively, and suitable mushroom head pushbuttons 39 and 40 are attached to the ends of the rods projecting from the face of the panel. Since the path of travel of the outer ends of the levers 24 and 25 is arcuate, the path of travel of each rod will not be coincidental with the longitudinal axis. of the rod. Therefore, to prevent binding or win- .43 and 44 limit outward travel, and similar stoppers 45 and 46 limit inward travel. Movement or displacement of the stoppers on the rods due to repeated bumping against the bushings is prevented in the case of stoppers 45 and 46 by the shanks of the pushbuttons 39 and 40, respectively, and is prevented in the case of stoppers 43 and 44 by the hollow tubular members 47 and 48, respec tively, which are disposed on the rods 33 and 34, respectively, between the stoppers 43 and 44 and the nut assemblies 49and 50; respectively.

' Figs. 1, 2 and 3' show a relatively large, substantially flat mounting plate 51 bolted to the upper surface of bearing screws which secure the cover 52 to the mechanism. Two

position, while lever 24 is shown moved to its extreme 7 operating position, that is, away from panel 22 as far as stopper 45 will allow. However, when rod 33 is not depressed spring 54 moves lever 24 to normal position.

Referring to Figs. 1 and 2, it is seen that pawl blocks 57 and 58 are pivotally attached to the underside of the levers 24 and 25, respectively, by the pins 59 and 60, respectively. Tension springs 61 and 62 are attached to the pawls57 and 58, which have portions adapted to engage the star wheel notches. The tension springs 61 and '62 are anchored to the relatively small angle brackets 63 and 64, respectively, which are rigidly secured to levers 24 and 25, respectively. If preferred, the springs 61 and 62 may be anchored directly to mounting plate 51 instead of to the respective lever arms, provided, of course, that suitable provisions are made therefor.

As Fig. 1 makes clear, when the levers 24 and 25 are biased in normal position, the tension springs 61 and 62 would tend to bias the pawls 57 and 58, respectively, against the throwout pins '65 and 66, respectively. The pawls are thus kept clearof the star wheel. If preferred, the throwout pins '65 and 66 may be rigidly secured directly to mounting plate 51. However, 'as it may be necessary to adjust the positions of these pins to com pensate for tolerances and to insure that the pawl blocks are properly disposed with respect to the star wheel, it is .desirable that the throwout pins 65 and 66 be afiixed to movable adjustment plates such as 67 and 68, respectively. The adjustment plates '67 and 68 are pivotally secured to mounting plate 51 by the rivets 69 and 70, re

spectively, but are normally held immobilized by thescrews 71 and .72, respectively, which extend through slots 'provided in the adjustment plates and take into tapped holes provided therefore in mounting plate 51.

Mounting plate 51 is provided with two rigidly attached stop posts 73 and 74 which have rectangular cross sections and which serve to limit the travel of the pawl blocks 57 and 58 as will hereinafter be explained.

To prevent undesired rotation of the drum cylinder, one of the notches of star wheel 17 is engaged by a roller 75 carried by the star wheel roller lever 76 which is pi-v- I otable on a pin or post .77 rigidly secured to mounting plate 51. A tension spring 78, having one end secured to a portion of roller lever 76 and its other end anchored to a bracket, 79 rigidly secured to mounting plate 51,

tends to bias roller 75 firmly against the star wheel.

Roller 75, while not preventing. intentional movement of the drum cylinder, tends to hold it in the position to which it is moved. a

Let it be assumed that the drum cylinder has a total of eleven definite operating positions with respect to the '2 1 Ttion of the star wheel. Star wheel 17 is shown disposed i 1.

in a centered position which correspondsto the sixth operating position of the drum cylinder. Assuming that both levers (and their associated parts) are biased in normal position, depression and release of pushbutton 39 would efiect rotation of the drum cylinder one step (a preselected distance) in the direction of the arrow (see Fig. 1) from position six to position five. Repeated actuation of push-button 39 would move it from position five to four. Obviously, actuation of pushbutton 40 would effect step-by-step movement of the drum cylinder in the direction opposite to the arrow (see Fig. 1). Each movement of the drum cylinder is accompanied by a correspondingchange in position of pointer 23a on hand wheel 23. Hand wheel 23 may be employed to rotate the drum cylinder in a rapid, continuous movement to its starting position, or other desired position, should stepby-step movement no longer be necessary, as when the controller is deenergized for any reason.

Although each step of drum cylinder rotation is effected by full depression of a pushbutton in a rapid, co-ntinuous stroke followed by release of the pushbutton, operation of the mechanism will be bestunderstood by a detailed "analysis of the movement of the drum one step in the direction of the arrow (see Fig. '1). As pushbutton 39 is depressed, rod 33 begins to move inward to effect pivoting of lever 24 in the direction of the arrow (see Fig. 1). Lever 24 carries pawl block 57 with it, but simultaneously tension spring 61 tends to pull the pawl block against and around throwout pin.65 so that the corner 57a of the pawl block is directed toward the star wheel. Corner 57a, which is rectangularly shaped to match the 'star wheel notches, slips into notch 17a. As lever 24 ad- 'vances further, pawl block 57 is moved away from throwout pin 65 and being engaged with a star wheel notch, efiects rotation of the drum cylinder. Rotation continues any preselected distance until lever travel is checked. *Lever travel may be checked either by having the pawl block 57 slam into stop post 73 or by having stopper 45 hit bushing35. Since the drum cylinder contemplated herein has considerable mass and momentum, the former method of stopping is accompanied by considerable shock and noise. Therefore, the latter method is preferred. By adjusting'the nut assembly which secures bracket 29 to' rod- '33, the stroke of lever 24 may be shortened so that resilient stopper 45 hits bushing 35 slightly before 'face 57b of pawl block 57 meets stop post.73. The momentum of the drum cylinder, however, causes the star wheel to thrust the pawl block against the stop post thus insuring that the drum cylinder has traveled its preselected distance but preventing the possibility of drum cylinder overtrayel. When notch 17a has moved to the position 17b the drum cylinder has been moved an exact, predetermined distance in a swift, sure movement. Pushbutton 39 is released and tension spring 55 tends to pull lever 24 back toward its normal position. Pawl block 57, due to the tapered configuration of that portion locking the drum against further rotation, is readily withdrawn from between the star wheel and stop post no matter how firmly the star wheel may have been thrust against it. Aslever 24 moves further back, spring 61 draws the pawl block against throwout pin 65 and clear {ofthe star wheel. It is essential that thepawl block be moved clear of the star wheel so that the mechanism bein readiness for movement of the drum cylinder in the reverse direction, should such be desirable. It is to be understood that lever. 25 and the parts associated therewith operate in a manner similar to that described to effect ,step-by-step rotation of the drum cylinder in the opposite direction. 1

Rotation of star wheel 17 beyond position one or eleven is impossible by movement of the levers since the pawl -blocks wou1 d be-brought into engagement with the unnotched portion'ofzthe star wheel, while further rotation through useof hand wheel 23 is prevented by the lugs 80 and 8'1=(Fig s. 2 and 3.) rigidly aflixed to the underside of the star wheel 17 which would come into abutment with the base of bearing support 15.

The mechanism is susceptible of various modifications. Star wheels having other shapes or greater or lesser num bers of notches may be employed provided that suitable changes are made in parts associated therewith. Thus, a star wheel notched completely about its periphery, and not provided with lugs 80 and 81, may be employed to obtain continuous step-by-step movement in either direction. If preferred, other lever moving arrangements may be employed, such as moving them directly or by electromagnetic means, or linkages requiring them to be pulled rather than pushed.

I claim:

1. In a step-by-step operating and positioning mechanism for a controller having a rotatable operating shaft, in combination, a star wheel to effect rotation of said shaft, an operating member normally biased to a given position and movable a predetermined distance against said bias, a pawl, means to afford engagement of said pawl with said star wheel and move the latter a given angular distance in one direction when said member is moved said predetermined distance against its bias, means acting upon said pawl when said operating member has moved said predetermined distance to stop rotation of said star wheel in said one direction, and means biasing said pawl out of engagement with said star Wheel when said member returns to its given position.

2. As a step-by-step operating and positioning mechanism for a controller having a rotatable operating shaft, in combination, a star wheel to effect rotation of said shaft, at least one operating member, said member normally disposed in a given position and movable a predetermined distance therefrom, a pawl movable by said operating member to effect rotation of said star wheel in one direction, said pawl normally disengaged from said star wheel when said operating member is disposed in said given position, means to effect engagement of said pawl with said star wheel as said operating member moves away from said given position, and means acting upon said pawl when said operating member has moved said predetermined distance to stop rotation of said star wheel in said one direction.

3. As a step-by-step driving and positioning mechanism for a drum controller having a drum member rotatable in forward and reverse directions, in combination, a star wheel to effect rotation of said drum member, at least one operating member pivotable about said star wheel, said member normally disposed in a given position and pivotable a predetermined distance therefrom, a pawl carried by said operating member to effect rotation of said star wheel in one direction, means to maintain said pawl disengaged from said star wheel when said operating member is disposed in said given position, said means effecting engagement of said pawl with said star wheel as said operating member moves away from said given position, and means acting upon said pawl when said operating member has moved said predetermined distance to stop rotation of said star wheel.

4. The combination according to claim 3 wherein said first mentioned means comprise biasing means associated with said pawl and fixed means against which and about which said pawl is biased.

5. As a step-by-step driving and positioning mechanism for a drum controller having a drum member rotatable in forward and reverse directions in combination, a star wheel to effect rotation of said drum member, a base, at least one operating member pivotable about said star wheel, said member normally biased in a given position with respect to said base and pivotable a predetermined distance therefrom, a pawl carried by said operating member to effect rotation of said star wheel in one direction, biasing means associated with said pawl, means fixed with respect to said base against which said pawl is biased when said operating member is disposed in said given position thereby maintaining said pawl disengaged from said star wheel, said means cooperating with said pawl to effect engagement of said pawl with said star wheel as said operating member moves away from said given position, and means fixed with respect to said base which engage said pawl when said operating member has moved said predetermined distance to prevent further rotation of said star wheel.

6. The combination according to claim 5 wherein said biasing means associated with said pawl is anchored to said operating member.

7. The combination according to claim 5 wherein said biasing means associated with said pawl is anchored to a point fixed with respect to said base.

8. The combination according to claim 5 wherein said pawl and said last mentioned means are shaped and disposed with respect to each other so that said pawl may be readily withdrawn from between said star wheel and said last mentioned means.

9. As a step-by-step driving and positioning mechanism for a drum controller having a drum member rotatable in forward and reverse directions, in combination, a star wheel to effect rotation of said drum member, two operating members, each member normally disposed in a given position and movable a predetermined distance therefrom, two pawls, one of said pawls movable by one of said operating members to effect forward rotation and the other movable by the other of said operating members to effect reverse rotation of said star wheel, each pawl normally disengaged from said star wheel when the operating member associated therewith is disposed in said given position, means to effect engagement of each pawl with said star wheel as the operating member associated therewith moves away from said given position, and means acting upon each pawl when the operating member associated therewith has moved said predetermined distance to stop rotation of said star wheel in the direction in which it is moving.

10. As a step-by-step driving and positioning mechanism for a drum controller having a drum member rotatable in forward and reverse directions, in combination, a star wheel to effect rotation of said drum member, two operating members pivotable about said star wheel, each member normally disposed in a given position and pivotable a predetermined distance therefrom, a pawl carried by each operating member, one pawl movable by one of said operating members to effect forward rotation of said star wheel and the other pawl movable by the other of said operating members to effect reverse rotation of said star wheel, means associated with each pawl to maintain said pawl disengaged from said star wheel when the operating member carrying said pawl is disposed in said given position, said means effecting engagement of said pawl with said star wheel as the operating member carrying said pawl moves away from said given position, and means acting upon each pawl when the operating member carrying each pawl has moved said predetermined distance to stop rotation of said star wheel.

11. As a step-by-step driving and positioning mechanism for a drum controller having a drum member rotatable in forward and reverse directions, in combination, a star wheel to effect rotation of said drum member, a base, two operating members pivotable about said star Wheel, each member normally biased in a given position with respect to said base and pivotable a predetermined distance therefrom, a pawl carried by each operating member, one pawl movable by one of said operating members to effect forward rotation of said star wheel and the other pawl movable by the other of said operating members to effect reverse rotation of said star wheel, biasing means associated with each pawl, means fixed with respect to said base against which each pawl is biased when the operating member associated therewith 1s disposed in said given position thereby maintaining each pawl disengaged from said star wheel, said means ciated therewith moves away from said given position, and means fixed with respectto said base which engage each pawl when the operating member associated therewith has moved said predetermined distance to prevent further rotation of said star wheel.

12. The combination according to claim 11 including means responsive to the movement of said drum member to indicate the position wherein said drum member is disposed.

13. The combination according to claim 11 including means to rotate said drum member in either direction when each pawl is disengaged from said star wheel.

14. As a step-by-step operating and positioning mechanism for a controller having a rotatable operating shaft, in combination, a star wheel to efiect rotation of said shaft, two operating members pivotable about said star wheel, each member normally biased to a given position and pivotable therefrom, means rectilinearly movable to move each operating member a predetermined distance, a pawl carried by each operating member, one

pawl movable to effect forward rotation of said star wheel and the other pawl movable by the other of said operating members to eifect reverse rotation of said star wheel, means associated with each pawl to maintain said pawl disengaged from said star wheel when the operating member carrying said pawl is biasedto said given position, said means efiecting engagement of said pawl with said star wheel when the operating member carrying said pawlis moved away from said given position, and means acting upon each pawl when the operating'member carrying each pawl has moved. said predetermined distance to stop rotation of said star wheel.

References Cited in the file of this patent UNITED STATES PATENTS 1,126,084 Reisbach Jan. 26, 1915 r 1,425,007 Granlund Aug. 8, 1922 2,488,766, De MOSS NOV. 22. 1949 FOREIGN PATENTS 686,920 Germany Jan. 18, 1940 

